CSC364 Lecture 14

Introduction to Networked, Distributed, and Parallel Computing
Patterns II
(202602)

Transcript

1. Dr. Javier Gonzalez-Sanchez javiergs@calpoly.edu www.javiergs.info o ffi ce: 14 -227 CSC 364 Introduction to Networked, Distributed, and Parallel Computing Lecture 14. Concurrency Design Patterns II 1
2. Immutable Object Pattern 2
3. 3 De f inition • An Immut a ble Object c a nnot be modi f ied a fter cre a tion. • Once constructed, its st a te never ch a nges. Wh a t does this p a ttern gu a r a ntee? • Thre a d s a fety by design • No synchroniz a tion required • No r a ce conditions When to Use Immut a ble Objects? • D a t a is sh a red a cross thre a ds • St a te does not need to ch a nge • Simplicity a nd s a fety a re priorities
4. 4 Code
5. 5 Code • final on a class prevents extension. • final on fields prevents mutation. • Immutability requires both — plus no setters.
6. Guarded Suspension Pattern 6
7. 7 De f inition • A thre a d w a its (is suspended) until a gu a rd condition becomes true. • Another thre a d l a ter ch a nges the st a te a nd sign a ls the w a iting thre a d to resume. Us a ge: • A Client thre a d w a nts d a t a . • A Worker thre a d produces the d a t a l a ter. • The client w a its s a fely until the d a t a is a v a il a ble.
8. 8 Main
9. 9 Worker
10. 10 Client
11. 11 Data
12. Pipeline Pattern 12
13. 13 De f inition • Work f lows through st a ges (thre a ds), typic a lly connected by blocking queues. • E a ch st a ge runs concurrently.
14. 14 Class Condition • A Condition object represents a st a te predic a te th a t thre a ds c a n w a it for while holding a lock. • E a ch Condition is tied to one speci f ic lock When a thre a d c a lls a w a it(): • It rele a ses the lock • It goes to sleep When sign a led: • It re- a cquires the lock • Execution resumes a fter a w a it()
15. 15 Main (1/2)
16. 16 Main (2/2)
17. 17 StageQueue
18. 18 Life Cycle
19. 19 ReaderStage
20. 20 ProcessorStage
21. 21 StorageStage
22. 22 Questions
23. Lab.
24. 24 Pac-man Arena
25. CSC 364 Introduction to Introduction to Networked, Distributed, and Parallel Computing Javier Gonzalez-Sanchez, Ph.D. javiergs@calpoly.edu Winter 2026 Copyright. These slides can only be used as study material for the class CSC 364 at Cal Poly. They cannot be distributed or used for another purpose. 25